Fault Analysis of the Blue Nile Grid

Abstract

The National Grid of Sudan (NG) was developing and facing significant and numerous changes in its topology and generation levels over the years. Reinforcements such as the 110KV Khartoum ring, additional transformers, uprating of old equipment and new power stations contribute to the increase in fault levels at all system busbars. As most of the switchgear and busbar ratings pertain to the early fault level calculations, it becomes necessary to undertake new fault levels analysis. This is helpful in ascertaining safe operation of the system and determining upgrading or changes in topology where required. In this study, a fault analysis programme was developed which enables study of all type of faults on the system busbars, with the aid of the programme, a complete fault level assessment of the NG was undertaken on the 220, 110, 33 and 11KV levels. The fault levels were found to exceed switchgear ratings in some cases and recommendations for limiting the fault currents are proposed. It is also noteworthy to mention that in the past, fault calculations were undertaken by Foreign Consultants while this programme enable NEC to carry out fault investigations whenever and wherever required.